Internal-combustion engine

ABSTRACT

An internal-combustion engine has cylinders  21  arranged preferably in a V-formation with corresponding cylinder heads ( 27 ) including connectors for the supply and discharge of fluids. The cylinders are mounted in a crankcase ( 41 ) and are supplied with air for combustion by a cast air manifold ( 51 ) running the length of the engine, the air manifold being located adjacent to the row of cylinders, preferably in the V. To reduce the amount of pipework the manifold has shaped connectors for at least one of the fluids, in particular the air intake ( 33 ) and the water coolant ( 55 ), these connectors connecting directly to the relevant connectors on the cylinder head and being pressed against them by the pressure in the manifold.

This application is a U.S. National Stage application of co-pending PCTapplication PCT/GB03/02406 filed Jun. 2, 2003, which claims the priorityof United Kingdom Patent Application No. 0212733.0, filed May 31, 2002.These applications are incorporated herein by reference in thereentireties.

BACKGROUND

The present invention relates to internal-combustion engines, inparticular large engines such as are used in fast boats such as ferriesor generally for industrial power generation.

Manufacturers of engines are of course always trying to increase thespecific power output of their engines. One way of doing this is byreducing the weight of the engine. Another important characteristic isthe ease of maintenance of such engines, which is partly dependent uponthe ease of access to the internal components. Also, of course, reducingthe cost of manufacture is a constant requirement. The present inventionaims to make improvements in all these areas.

For background on the layout of engines one can consult the followingdocuments. U.S. Pat. No. 3,809,032 (G O Morris) describes a manifold forwith separate passages for a multiple-barrel carburettor. U.S. Pat. No.4,267,812 (Ford) shows a manifold system providing an integral mountingof an EGR cooler/carburettor. U.S. Pat. No. 4,458,491 (MTU) has anexhaust manifold system within the V of a V-engine. U.S. Pat. No.6,032,634 (Hitachi) shows a multi-part engine air manifold systemlocated on the engine, where two design options are provided for anoptimised air charging system as well as providing cooling for theengine control unit. The manifold system includes a longitudinalpartition wall and mounts other engine components such as the injectors.JP 10-030445A (Nissan) shows an intake manifold with an integralsupercharger, mounted on top of the engine. EP 0162272 A1 (KHD) shows anenclosed assembly containing lubricant and fuel pipes. EP 0644326 A1(Hitachi) is an air duct with integral air filter/throttle valve and aplurality of suction pipes. Described in EP 1069301 A2 (DDC) is awedge-shaped cylinder head with integral air manifold mounted on top ofand spanning the cylinder heads. Finally GB 2174454 A (Rover) shows anair induction system with variable plenum length. The design allows easeof manufacturing by plastic mouldings and metal pressing.

SUMMARY OF THE INVENTION

According to the invention there is provided an internal-combustionengine having cylinders arranged in a row with corresponding cylinderheads including connectors for the supply and discharge of fluids, thecylinders being mounted in a casing and being supplied with air forcombustion by an air manifold running the length of the engine, in whichthe air manifold is locked adjacent to the row of cylinders, and hasshaped connectors for at least one of the fluids, these connectorsconnecting directly to the relevant connectors on the cylinder head.

This arrangement does away with at least some of the piping between theair manifold and the cylinders that is a feature of prior-art engines.The connecting parts of air manifold and cylinder head abut each otherdirectly, but a good seal can nevertheless be achieved because (incontrast to the engines described above) the pressure in the airmanifold during operation of the engine presses outwards and seals theconnection.

For pressure within the air manifold to improve the seal of theconnectors on the manifold abutting against the cylinder heads theremust be a support opposite the cylinders against which the air manifoldcan bear. For an in-line engine a special support can be designed, butthe invention is particularly advantageous for V-engines because themanifold can simply be located within the V, between the rows ofcylinders, in use bearing outwardly against them on both sides.Preferably it rests directly on the crankcase, and the connectors aredesigned to have substantially vertical planes of abutment.

The fluid or fluids in question can be combustion fluids, such as theair directed towards the inlet valves in the cylinder head, orheat-exchange fluids, in particular the water used for cooling thecylinders. Advantageously both such possibilities are made use of, sothat the air manifold has no external pipes along its length (though itwill generally have pipes at the end for supply and discharge).

It is possible to achieve further integration if further channels, notnecessarily communicating directly with the cylinder heads and being forinstance for oil and/or water, are integrated into the manifold,preferably on its underside, i.e. adjacent to the casing, in other wordsthe crankcase. Moreover, in the part between the rows of cylinders anddirectly under the air manifold the crankcase may itself containpassages for water, one over the other, the upper or outer one of whichis sealed directly by the air manifold, i.e. the wall of the manifoldalso forms part of the wall of the passage. This reduces the number ofparts of the engine. Furthermore the intercooler for a turbochargerarrangement can be mounted directly on top of the air manifold. Thisdoes away with the support brackets that would otherwise be needed,saving weight and space. The air manifold is preferably cast, so as tobe able to achieve the necessary shape, and may for instance be ofaluminium. With the intercooler supported along its entire length on themanifold the strength of aluminium is entirely adequate.

For a better understanding of the invention an embodiment will now bedescribed with reference to the accompanying drawings, in which:

FIG. 1 shows a perspective view of a complete engine, representing anembodiment of the invention;

FIG. 2 shows a cross-section through the engine perpendicular to theaxis; and

FIG. 3 shows a perspective view of the engine with the cylinder headsremoved showing the air manifold; and

FIG. 4 shows the air manifold itself.

FIG. 1 shows a V12 engine which can be used, for instance, in fastcross-channel ferries. The cylinder head 27 on one side can be seen, ascan the intercooler 61 on top of the engine and next to it on eitherside the exhaust heat shields 73. All the drives are at one end of theengine, and in the Figure the lubricating oil pump 85, sea water pump 89and fresh water pumps 91 can be seen. Also visible is a damper 87 andthe twin air filters 93 leading into the turbochargers which in turnlead via twin emergency shut-off valves 97 into the intercooler 61.

FIG. 2 shows a cross-section though this engine. The engine is of amodular design and can be produced in varying configurations—currentlyas a twelve-, sixteen- or twenty-cylinder engine—with a minimal stock ofparts such as air manifold, cylinder head. The section is taken througha crank 3 of the crank shaft 1 to which is connected a two-piecedowelled angle split connecting rod 5 leading to the gudgeon pin 7 atthe small end. The gudgeon pin is connected in the usual way to a piston11 which in its crown 13 has a central chamber 14 surrounded by anannular chamber 15. To form the chambers the piston is made in two partssplit by a plane perpendicular to its axis by a proprietary process.

The piston 11 slides in cylinders 21 having at their upper ends, i.e. atthe ends away from the crank shaft, a thicker portion 23 surrounded by asleeve or water jacket 25 defining the chamber for cooling of thecylinder. On top of each cylinder is a cast cylinder head 27 with twopairs of valves 29 mounted in the usual way. The cylinder head is castin iron and has an exhaust outlet 31 and an air inlet 33. The cylindersare mounted in a V formation in a cast crankcase 41, being sealed to itapproximately at the bottom end of their thicker portions 23. Thecrankcase contains at least one passage, here two cast passages 43 and45, for water running axially to the engine, located generally in the Vbetween the lower ends of the cylinder liners 21. The upper passage 45is the hot feed to the cylinder heads, and the lower passage 43 is thecold return.

An air manifold 51, likewise made of cast aluminium and having agenerally rectangular section with side-walls 52, runs the length of theengine and is mounted approximately between the cylinder heads 27 of thetwo banks of cylinders. The manifold 51 has a central passage runningalong its length and off this passage along each side in the sidewalls52 has air terminals or connectors 59 that abut the ends of the airpassages 33 of the cylinder heads. The plane of their abutment issubstantially vertical, i.e. perpendicular to the axis of the V.Likewise the manifold 51 has, near the top of the sidewalls, integralcast passages 55 for hot water that communicate with a chambersurrounding the exhaust passages 31 in the cylinder heads. In use thepressure in the manifold pushes the sidewalls 52, with the connectingterminals, outwards against the corresponding terminals on the cylinderheads, reinforcing the sealing effect.

The air manifold 51 also has twin axial water and oil passages 53 in itsbottom section, the lower walls of which act to seal the upper waterpassage 45 in the crank casing. The water passage in the air manifoldsupplies cold water to a second intercooler, if present.

On top of the air manifold 51 is mounted the intercooler 61 which is atwo-stage intercooler with integral air intake passage, surrounded by asingle casing which has a waist so that it forms a figure of eight insection, the upper part being the air passage and the lower partenclosing the heat exchanger pipes 63. A line can also be seen whichnotionally splits the intercooler into two stages: the pipes above thisline are connected to the hot (c. 80° C.) water from the passages 55,and the pipes below are connected to the cold (c. 40° C.) supply. Theair spreads axially along the air passage and then down between thepipes and into the manifold. Next to the intercooler on either side arethe exhaust manifolds 71 connected to the exhaust passages 31 of thecylinder heads, again directly. The exhaust manifolds are protected bycovers 73, which as can be seen are in two parts.

FIGS. 1 and 2 also shows the cam shafts 101, the fuel pump 105, the sump83, twin bearing caps 85 and cast mounting feet 81 for mounting theengine in a frame, such as a ship's frame, the lubricating oil cooler74, an intercooler water diverting valve 57, a duplex lubricating oilfilter 76, a fuel pump and tappet cover 77, crankcase doors 79, alubricating oil pump 84 and a lubricating oil filler 86. For atwelve-cylinder ferry engine the bore is 280 mm, the stroke is 330 mmand the power output may be about 5.4 MW at a speed of about 1000 r/min.However the invention is not limited to ships' engines.

FIG. 3 shows a 16-cylinder version of the engine in perspective, withthe cylinder heads 27 removed so that the air manifold box 51 isvisible. The cast air connections 59, a pair for each cylinder, arevisible. In the 16-cylinder version (as for the 20-cylinder) twointercoolers 61 are used, the cold water supply to the second being byway of one of the lower passages 53 in the manifold. The manifold 51 isshown on its own in FIG. 4, the seals between sections also being shownin a partially exploded view that reveals the hot-water passages 55.These Figures also show the modular nature of the engine and manifold,the cross-section of the manifold being essentially uniform, withpassages running only axially within it along its length.

1. An internal-combustion engine having cylinders arranged in two rowsin a V-formation with corresponding cylinder heads including connectorsfor the supply and discharge of fluids, the cylinders being mounted in acasing and being supplied with air for combustion by an air manifoldrunning the length of the engine, in which the air manifold is locatedwithin the V of the engine, between the row of cylinders, and hassidewalls with shaped connectors for at least one of the fluids, theshaped connectors of the sidewalls connecting directly to the connectorsof the cylinder heads along a parting plane that is substantiallyvertical, and in use the shaped connectors of the sidewalls beingpressed against the connectors of the cylinder heads by the pressure inthe manifold.
 2. An engine according to claim 1, in which the fluid orfluids include combustion fluids, such as the air directed towards theinlet valves in the cylinder head, or heat-exchange fluids, inparticular water used for cooling the cylinders, or both.
 3. An engineaccording to claim 1, in which the air manifold has no external pipesalong its length, and contains passages for the fluids that runessentially along its entire length.
 4. An engine according to claim 3,in which further channels, not communicating directly with the cylinderheads and being for instance for oil and/or water, are integrated intothe air manifold.
 5. An engine according to claim 1, in which, in thepart adjacent to the row of cylinders and directly under the airmanifold, the engine crankcase itself contains passages for water, theupper one of which is sealed directly by the air manifold.
 6. An engineaccording to claim 1, further comprising an intercooler for aturbocharger arrangement, mounted directly on top of the air manifold.7. An engine according to claim 1, in which the air manifold is cast,for instance of aluminum, and has a generally rectangular cross-section.8. An engine according to claim 1, in which the air manifold is ofmodular design, being adapted to be fitted to further such manifolds,end to end.
 9. A water craft having an engine according to claim
 1. 10.An internal-combustion engine having cylinders arranged in two rows, ina V-formation, with corresponding cylinder heads including connectorsfor the supply and discharge of fluids, the cylinders being mounted in acasing and being supplied with air for combustion by an air manifoldrunning the length of the engine, in which the air manifold is locatedwithin the V of the engine, between the rows of cylinders, and hasshaped connectors for at least one of the fluids, these connectorsconnecting directly to the relevant connectors on the cylinder head, andfurther channels, not communicating directly with the cylinder heads andbeing for instance for oil and/or water, integrated into the lower partof the air manifold and running along its length.
 11. An engineaccording to claim 10, wherein in which the engine is a V-engine and themanifold with further channels is located within the V.
 12. Aninternal-combustion engine having cylinders arranged in two rows in aV-format with corresponding cylinder heads including connectors for thesupply and discharge of fluids, the cylinders being mounted in a casing;and an air manifold running the length of the engine, the cylindersbeing supplied with air for combustion by the air manifold; in which theair manifold is adjacent to and located within the V, between the rowsof cylinders, and has sidewalls with shaped connectors for at least oneof the fluids, the shaped connectors of the sidewalls connectingdirectly to the connectors of the cylinder heads along a parting planethat is substantially vertical, and in use the shaped connectors of thesidewalls being pressed against the connectors of the cylinder heads onboth sides by the pressure in the manifold; in which the air manifoldhas no external pipes along its length, and contains passages for thefluids that run essentially along its entire length, including furtherchannels for instance for oil and/or water, not communicating directlywith the cylinder heads and integrated into the air manifold; and inwhich, in the part adjacent to the rows of cylinders and directly underthe air manifold, the engine crankcase itself contains passages forwater, the upper one of which is sealed directly by the air manifold bythe pressure in the manifold.
 13. An engine according to claim 12,further comprising an intercooler for a turbocharger arrangement,mounted directly on top of the air manifold.
 14. An engine according toany claim 12, in which the air manifold is cast of aluminum and has agenerally rectangular cross-section.